Vertical steam boiler



I 5. wt. FLEMING VERTICAL SETEAM BOILER Filed March 20, 1945 Attorney Patented Jan. 14, 1947 VERTICAL STEAM BOILER Samuel William Calderwood Fleming, Strathaven, Scotland Application March 20, 1945, Serial No. 583,805 In Great Britain February 28, 1944 3 Claims.

This invention relates to steam boilers of the so-called vertical type, that is to say steam boilers whose internal components are built inside a shell structure the main axis of which is vertical.

The invention is especially intended for application to small-output steam boilers such for example as would be used for the propulsion of small steam ships and for auxiliary purposes on large ships.

The object of this invention is to provide a water-tube steam boiler of the type stated whi h will be simple in construction and efiicient in use and which can be designed for any given small output to have reduced overall dimensions rendering such a boiler suitable for installations in places where space is an important consideration. Another object is to provide a water-tube steam boiler in which an internal flue leads from the furnace into an annular combustion chamber at one side thereof, an uptake for the hot products from the chamber is arranged at the side of the chamber opposite the fine and an internal downcomer between water spaces respe tively above and below the chamber is oiTset in relation thereto so that the cross-sectional area of the chamber reduces between the flue side thereof and the uptake side thereof. The arrangement is such that the hot products sweep with substantially uniform speed across water tubes extending between said water spaces in the flow of such products from the flue around the annular combus tion chamber to the uptake.

The invention will now be described by way of example with reference to the accompanying drawing, in which- Fig. 1 is a sectional elevation of a steam boiler according to the invention, the section being on the line I--I of Fig. 3.

Figs. 2 and 3 are fragmentary sections on the lines II-II and III-III of Fig. 1 respectively.

The steam boiler shown is of the so-called vertical type, that is to say its internal components are built inside a cylindrical shell la. lb and lo the axis AA of which is vertical. v The said components comprise an internal downcomer 2, an annular passage within the intermediate shell portion lb forming a combustion chamber 3 (Fig. 3) for the hot products between the downcomer 2 and the shell, said chamber being bounded top and bottom by tube-plates 4 and 5, respectively, upcomers in the form of water tubes 8 extending through the chamber 3 from tubeplate to tube-plate, a furnace 1 separated from the chamber 3 by a water space 8 within the lower shell portion lc but connected with the chamber 3 by an internal flue 9, and an uptake Illa, lllb provided on the shell exterior in register with the chamber 3. The arrangement is such that the hot products sweep across the water tubes in their flow from the flue around the annular combustion chamber to the uptake. The shell has slightly domed top plate I I.

In the example, the downcomer 2 is cylindrical and is set e centrically in the shell I so that as hereinafter more fully explained, the cross-sectional area of the combustion chamber 3 gradually reduces as between the vicinity of the flue 9 and the vicinity of the uptake. The arrangement is such that the rate of reduction in cross-section corresponds to the estimated reduction in volume of the products in the chamber as they lose their heat, so that there will be substantial uniformity in the speed of the hot products through the chamber.

The smokebox portion lflb of the uptake is built on the shell portion lb about midway of the height of the shell. The chamber forming the furnace 'l is built into the bottom of the shell, being roughly hemispherical in form. The internal flue 9, whi h may be elliptical, as Fig. 3

' shows, or cylindrical, is arranged in the same central vertical plane 13-13 (Fig; 2) as the uptake and is built at an upward and outward inclination at the side opposite the uptake between the furnace chamber top and the lower-of the two horizontal tube-plates 4 and 5. The down comer 2 is a vertical-axis cylinder extending from one tube-plate .to the other and having its axis offset from the boiler shell axis AA towards the uptake. Thus, the annular passage constituting the combustion chamber 3 formed by the downcomer cylinder 2 and intermediate shell portion l b at the sides and by the tube-plates 4 and 5 at the top and bottom varies gradually in crosssectional area from a maximum above the flue to a minimum beside the uptake. The water tubes 6 in the combustion chamber are arranged therein as two banks of short straight vertical tubes, and these include a suitable proportion of stay tubes, all the tubes being equal in length and being connected, in usual manner, at their top and bottom ends to the tube-plates, being insertable and withdrawable through the upper tube-plate l. Each of the two banks of tubes extends in an are (as viewed in plan, Figs. 2 and 3) from one side of the flue 9 to the uptake. Between the lower tube-plate 5 and the furnace top there is the lower water space 8. The hemispherical form of the furnace chamber surmounts an annular pocket 8a as the lowest portion of the lower water space. Between the upper tubeplate 4 and the boiler top H, the upper shell portion la encloses a drumlike water and steam space [2,

The annular passage, in view of its function as the combustion chamber 3, is lined around the downcomer '2 in proximity to the fluelf; with firebricks l'3 that-are'held in place by adjacent water tubes 6; and the chamber 3 is lined around the shell portion lb by firebricks l4. These bricks l' i are held by bolts Ma to the portion lb, which is a casing composed of detachable plates flangejointed together (Fig. 3).

The upper tube-plate 4 is stayed by above the flue 9.

In the shell there is a mandoor 16 above the upper tube-plate and there is also a mandoor ll below the lower tube-plate, so that the interior of the boiler is all accessible for cleaning, inspection and repair. The refractory bricks i i and the plating of the casing I b, being removable, permit cleaning ofthe flresurfaces of the tubes and tubeplates. Likewise, the front plating Hie oi the smokebox is removable.

At the lowest points of the lower water space S,

that is on the annular pocket 8a, there are fitted a blow-down valve ISand a wash-out lug by virtue of which latter the boiler interior can be completely drained of all water and sediment after cleaning. The boiler would have the usual mountings, including a stop-valve (not shown) on the steam outlet facing 20, which is fitted with the usual steam collector 2|, and a feed-water check-valve (also not 'shown) on the feed inlet facing 22.

The feted-waterin the example is led from the inlet 22 by a pipe 23 through the lower water space 8 to the downcomer 2. The pipe 23 rises up one side of the downcomer and spreads in arcuate perforated arms 24 around part of the inner periphery of the downcomer top end.

It will be noted that'the wall of the furnace i abuts against a cylindrical soleplate la extending beyond the annular pocket 8a to provide the support of the boiler shell and to serve as an ashpit below the firebars 25 of the furnace.

In use of the boiler, the water from the perforated arms .24 flows down the downcomer cylinder 2 into the lower water space 8, whence it rises through the water tubes to the waterand-steam space l2 above, returning downwards with still incoming feed water and continuing to circulate in this way. The hot products from the furnace 1 pass up the flue 9 into the combustion chamber 3 along which they sweep horizontally in both directions amongst the water tubes to the uptake l0, into which they are guided by curved plating 2B.

The efficiency of the boiler is due largely to the arrangement whereby the hot products sweep at right angles across the water tubes and the arrangement of short straight vertical tubes from gussets l 5 which the steam generated has practically unrestricted discharge.

I claim:

l. A steam boiler comprising an outer shell structure, an internal downcomer, an annular passage forming a combustion chamber for the hot products between said downcomer and the shell structure, tube-plates secure'dto said shell structure and arranged to bound said chamber top and bottom, upoomers in the form of water tubes extending through said chamber from one of said tube-plates to the other, a furnace separated from said chamber by a water space, an internal flue connecting said furnace with said chamber, and an uptake provided on the shell structure in register with said chamber, said downcomer being offset from the axis of said shell structure so that the cross-sectional area of said chamber reduces between the vicinity of said fluid and the vicinity of said uptake.

2. A steam b'oi'ler of the type having a vertical cylindrical shell structure, comprising an internal downcomer formed as a vertical cylinder, an annular passage forming a combustion chamber for the hot products between said downcomer and said shell structure, tube-plates secured to said shell structure and arranged to beundsaid chamber top and bottom, .upco'mers in the fer-in of water tubes extending through said chamber from one of said tube-plates to the other, a furnace separated from said chamber by a water space, an internal flue connecting said furnace with said chamber, and an uptake provided on the shell structure in register with said chamber, the cylindri al downcomer being eccentric to said shell structure so that the cross-sectional area of said chamber reduces between the vicinity of said flue and the vicinity of said uptake.

3. A steam boiler comprising a shell structure composed of an upper portion enclosing a waterand-steam space, a lower portion enclosing a water space and an intermediate cylindrical casing, upper and lower tube-plates forming the bottom and top of said spaces respectively, a cylindrical internal downcomer interconnecting said spaces and forming with said tube-"plates and intermediate casing a combustion chamber that extends round said downcomer, upcomers in the form of water tubes extending through'said chamber from one of said tube-plates to the other, a furnace built into the bottom of said lower portion of the shell structure, an internal fluid leading from said furnace through the lower of said tube-plates into said chamber, and an uptake for products from said chamber, said uptake being arranged at a side of said chamber opposite said flue and said'downcomer being eccentric to said casing so that the cross-sectional area'of said chamber reduces between the flue side of said chamber and the uptake side thereof.

SAMUEL WILLIAM l CALDEHWOGD FLEMING. 

